I Have a 340 with a 727 trans that was sitting for 20 years. I got it started and drove up the driveway and back with no problems so I continued with progress on it. I hoooked up the kickdown cable and adjusted it as per instructions ( WOT and Kickdown pushed rearward all the way) and now I have no gears. No forward, no reverse, not even an attempt at movement. What went wrong?

 

I would start by going backwards. We didn't adjust them that way at the dealer. In the idle position (not running) the pivot arm where the linkage goes back from the carb there's a hole going through the levers. take a drill or shaft that fits the hole. Adjust the linkage so they all lineup so the drill slides freely. It should shift from first to second at 18 mph and into third at 36 mph at normal acceleration. I would think you'd still have movement either way but i would start with square one first. Fluid check in neutral, and then see if the shift linkage on the tranny got loose or popped off the halfmoon shaft.

 

What color is the fluid?
Dose it smell burt?
check the fluid level and make sure it has fluid...... If thats good? I would back off the Throttle Valve about 1/4" and see if thing came back?